1994 850T Tempertaure guage ECT low

cBobs94850T · Post by **cBobs94850T** » 28 Apr 2014, 10:15

The ECT has decided to randomly function. Sometimes it read the proper temp (3 O'clock position ) sometimes just barely off the bottom, then nothing. I have no error codes in A2, and I cannot read any in A6 light doesn't even light. Is this indicative of a faulty ECT or could there be something going on. Also is there a fix for the A6

thanks

Post by **Ozark Lee** » 28 Apr 2014, 10:55

On a '94 turbo you have a Motronic ECU and all of the codes are read through A-2. A-6 is only used on the older N/A cars with the LH 3.2 system.

Check the connector on the ECT sensor for corrosion or a broken wire if it is intermittent.

...Lee

cBobs94850T · Post by **cBobs94850T** » 28 Apr 2014, 11:13

Thank you Lee will check the connector
But lately it's been reading just slightly off the bottom, then falls to the bottem and back to slighty above
The RPM spike when it does this.

Post by **jblackburn** » 28 Apr 2014, 11:37

cBobs94850T wrote:Thank you Lee will check the connector
But lately it's been reading just slightly off the bottom, then falls to the bottem and back to slighty above
The RPM spike when it does this.

That's interesting. I'd hunt around for a corroded or loose ground strap, either by the ECU box or battery.

cBobs94850T · Post by **cBobs94850T** » 28 Apr 2014, 12:01

Thanks jblackburn

Post by **polskamafia mjl** » 28 Apr 2014, 14:20

I have a similar issue. Tach, fuel, and coolant gauges will work intermittently with coolant being the least likely to work usually. Its worst when its hot outside. Usually I can flick the malfunctioning gauge and it'll come back on. I think the clusters wear out after almost 20 years on the road. I have a working used cluster I'm going to install; hopefully that fixes my problems.

Post by **E Showell** » 29 Apr 2014, 13:19

That could also be a sign of incipient ECT failure. If there is no corrosion in the connector and no degraded wiring, I'd be looking to replace that ECT and thermostat asap.

Post by **cn90** » 29 Apr 2014, 13:51

How old is the thermostat?
If you replace, use only Wahler.

Post by **jreed** » 29 Apr 2014, 14:04

A couple of months ago I replaced a failed FAE ECT. I measured it and found it was reading too high a resistance compared to specification. I put up a graph and some inspection photos here:
https://www.matthewsvolvosite.com/forums ... =1&t=61920
I installed an OEM ECT sensor and it has been working fine since.